nervous system Flashcards
(25 cards)
what are the 2 main divisions of the nervous system?
CNS- central nervous system
PNS - peripheral nervous system
what 2 structures make up the central nervous system
- brain
- spinal cord
what is the order of events from stimulus to response?
stimulus –> receptors –>neural network/brain –> effectors(motor nerves) –> response
What are afferent nerves
sensory nerves that bring information into the central nervous system
what are efferent nerves
motor nerves that deliver information from the CNS to the PNS
what type of signals do neurons transmit
chemical and electrical signals
what is a dendrite?
branches at the start of the nerve that receive and send messages to travel along the cell body
what is an axon?
long extension of a neuron that carries nerve impulses AWAY from the cell body
what is the function of the myelin sheath?
speed up the action potential(signal)
what is the space between 2 neurons
a synapse
what are the 3 types of neurons?
motor, sensory, interneurons
what is the threshold of excitation?
strength of a stimulus needed to induce an action potential
what is reuptake
the reabsoprtion of neurotransmitterby a presynaptic neuron after it has performed its function of transmitting a neural impulse
what is postsynaptic
term to describe the cell that is receiving the neurotransmitter during synaptic transmission
presynaptic neuron
the neuron that is releasing the neurotransmitter
what is repolarization
after sodium ions have rushed into the cell, potassium ions rush out of the cell to restore the balance and the original polarity
what are neurotransmitters
chemical messengers that cross the synaptic gaps between neurons
what is a neuron?
a nerve cell that is specialized to receive and conduct electrical impulses
what is saltatory conduction?
the rapid skipping of an action potential from node to node on myelinated neurons
threshold stimulus
the minimal level of stimulation required to cause an action potential
what is the impulse that travels between neurons?
chemical impulse
what is the impulse that travels across neurons?
electrical current
subthreshold stimulus
a stimulus too small to create an action potential in a neuron
what is depolarization
the process during the action potential when sodium is rushing into the cell causing the interior to become more positive
